Refactor eval functions

pkg/config/config.go

@@ -24,6 +24,7 @@ import (
 	"strings"
 
 	"github.com/agext/levenshtein"
+	"github.com/hashicorp/hcl/v2"
 	"github.com/pkg/errors"
 	"github.com/zclconf/go-cty/cty"
 	"gopkg.in/yaml.v3"
@@ -720,14 +721,17 @@ func (bp *Blueprint) evalVars() (Dict, error) {
 		return Dict{}, err
 	}
 
-	res := Dict{}
+	res := map[string]cty.Value{}
+	ctx := hcl.EvalContext{
+		Variables: map[string]cty.Value{},
+		Functions: functions()}
 	for _, n := range order {
-		v := bp.Vars.Get(n)
-		ev, err := evalValue(v, Blueprint{Vars: res})
+		ctx.Variables["var"] = cty.ObjectVal(res)
+		ev, err := eval(bp.Vars.Get(n), &ctx)
 		if err != nil {
 			return Dict{}, BpError{Root.Vars.Dot(n), err}
 		}
-		res.Set(n, ev)
+		res[n] = ev
 	}
-	return res, nil
+	return NewDict(res), nil
 }

pkg/config/dict.go

@@ -97,7 +97,7 @@ func (d Dict) IsZero() bool {
 func (d Dict) Eval(bp Blueprint) (Dict, error) {
 	var res Dict
 	for k, v := range d.Items() {
-		r, err := evalValue(v, bp)
+		r, err := bp.Eval(v)
 		if err != nil {
 			return Dict{}, fmt.Errorf("error while trying to evaluate %#v: %w", k, err)
 		}

pkg/config/expand.go

@@ -82,7 +82,7 @@ func validateModuleInputs(mp ModulePath, m Module, bp Blueprint) error {
 }
 
 func attemptEvalModuleInput(val cty.Value, bp Blueprint) (cty.Value, bool) {
-	v, err := evalValue(val, bp)
+	v, err := bp.Eval(val)
 	// there could be a legitimate reasons for it.
 	// e.g. use of modules output or unsupported (by ghpc) functions
 	// TODO:

pkg/config/expression.go

@@ -144,8 +144,8 @@ func TraversalToReference(t hcl.Traversal) (Reference, error) {
 
 // Expression is a representation of expressions in Blueprint
 type Expression interface {
-	// Eval evaluates the expression in the context of Blueprint
-	Eval(bp Blueprint) (cty.Value, error)
+	// Eval evaluates the expression in the given context
+	Eval(ctx *hcl.EvalContext) (cty.Value, error)
 	// Tokenize returns Tokens to be used for marshalling HCL
 	Tokenize() hclwrite.Tokens
 	// References return Reference for all variables used in the expression
@@ -213,12 +213,8 @@ type BaseExpression struct {
 }
 
 // Eval evaluates the expression in the context of Blueprint
-func (e BaseExpression) Eval(bp Blueprint) (cty.Value, error) {
-	ctx := hcl.EvalContext{
-		Variables: map[string]cty.Value{"var": bp.Vars.AsObject()},
-		Functions: functions(),
-	}
-	v, diag := e.e.Value(&ctx)
+func (e BaseExpression) Eval(ctx *hcl.EvalContext) (cty.Value, error) {
+	v, diag := e.e.Value(ctx)
 	if diag.HasErrors() {
 		return cty.NilVal, diag
 	}
@@ -374,10 +370,18 @@ func valueReferences(v cty.Value) map[Reference]cty.Path {
 	return r
 }
 
-func evalValue(v cty.Value, bp Blueprint) (cty.Value, error) {
+func (bp *Blueprint) Eval(v cty.Value) (cty.Value, error) {
+	ctx := hcl.EvalContext{
+		Variables: map[string]cty.Value{
+			"var": bp.Vars.AsObject()},
+		Functions: functions()}
+	return eval(v, &ctx)
+}
+
+func eval(v cty.Value, ctx *hcl.EvalContext) (cty.Value, error) {
 	return cty.Transform(v, func(p cty.Path, v cty.Value) (cty.Value, error) {
 		if e, is := IsExpressionValue(v); is {
-			return e.Eval(bp)
+			return e.Eval(ctx)
 		}
 		return v, nil
 	})

pkg/config/expression_test.go

@@ -198,7 +198,7 @@ func TestFlattenFunctionCallExpression(t *testing.T) {
 		cty.NumberIntVal(2),
 		cty.NumberIntVal(3)})
 
-	got, err := expr.Eval(bp)
+	got, err := bp.Eval(expr.AsValue())
 	if err != nil {
 		t.Errorf("got unexpected error: %s", err)
 	}
@@ -226,7 +226,7 @@ func TestMergeFunctionCallExpression(t *testing.T) {
 		"two": cty.NumberIntVal(2),
 	})
 
-	got, err := expr.Eval(bp)
+	got, err := bp.Eval(expr.AsValue())
 	if err != nil {
 		t.Errorf("got unexpected error: %s", err)
 	}